C64 Dreams is a massive curated collection of C64 games, SID tracks, demoscene, diskmags, and magazines. It's a major labor of love, that's the result of (as of this version) four years of my life and literally thousands of hours of work.
I would highly encourage you to check out the video here for an overview of the project, feature demonstration, etc. You can also find the script/written guide here.
To summarize briefly, it is a collection of 3000 hand-curated games that have all been configured as needed on a game by game basis. Features included are:
Per-game joystick port settings
Per-game TrueDrive settings
Per-game border cropping
Smart controls that take advantage of modern controllers
Easy disk swapping (via keyboard or controller)
Custom per-game notes (toggleable in-game)
Manuals on demand (toggleable in-game); with nearly 1500 included manuals
Extra goodies like custom SID music added to text adventures that ordinarily have none and Zzap!64 review integration directly into the library so that you can right-click on a game in the library and jump straight to its review in Zzap!64, either via the web-reader or with (higher quality) local versions if you have the magazine module installed